McCance & Huether’s Pathophysiology
The Biologic Basis for Disease in Adults
and Children
9th Edition
Author(s)Julia Rogers
TEST BANK
Q1. A 6-year-old child is diagnosed with a rare inherited
disorder involving defective mitochondrial oxidative
phosphorylation. During periods of fasting, the child develops
profound fatigue, muscle weakness, and lactic acidosis. The
accumulation of lactate most directly reflects failure of which
cellular process?
,A. β-oxidation within peroxisomes
B. Anaerobic glycolysis secondary to impaired ATP production
C. Glycogenolysis within hepatocyte lysosomes
D. Increased pentose phosphate pathway activity
E. Enhanced gluconeogenesis in skeletal muscle
Correct Answer: B
Rationale:
• Clinical Clue: Fasting intolerance with lactic acidosis
suggests impaired aerobic energy generation.
• Mechanism: Dysfunctional oxidative phosphorylation
reduces ATP production, forcing cells to rely on anaerobic
glycolysis with lactate generation.
• Why the Correct Answer Is Right: Anaerobic glycolysis
becomes the major ATP source when mitochondria cannot
effectively use oxygen.
• Why the Other Options Are Wrong:
o A: Peroxisomal β-oxidation does not directly explain
lactate accumulation.
o C: Glycogenolysis occurs in cytoplasm, not lysosomes.
o D: Pentose phosphate activity generates NADPH, not
lactate.
o E: Skeletal muscle is not a major gluconeogenic organ.
, • Exam Trap: Do not confuse mitochondrial failure with
hypoxia alone; both can produce lactic acidosis through
impaired aerobic metabolism.
• High-Yield Clinical Correlation: Mitochondrial diseases
often affect tissues with high energy demand such as
muscle and nervous tissue.
• Memory Anchor: “Broken mitochondria push cells toward
lactate.”
Q2. A researcher selectively disrupts microtubule
polymerization in rapidly dividing tumor cells. Shortly
afterward, the cells arrest during mitosis. Which function is
most directly impaired?
A. Formation of gap junctions
B. Synthesis of ribosomal RNA
C. Segregation of chromosomes during metaphase
D. Oxidative phosphorylation
E. Packaging of proteins within the Golgi apparatus
Correct Answer: C
Rationale:
• Clinical Clue: Arrest during mitosis strongly implicates
spindle dysfunction.
• Mechanism: Microtubules form the mitotic spindle
required for chromosome separation.
, • Why the Correct Answer Is Right: Chromosome alignment
and segregation depend on intact microtubules.
• Why the Other Options Are Wrong:
o A: Gap junctions are formed by connexins.
o B: Ribosomal RNA synthesis occurs in the nucleolus.
o D: Oxidative phosphorylation occurs in mitochondria.
o E: Golgi function relies more on vesicular trafficking
than spindle formation.
• Exam Trap: Microfilaments are commonly confused with
microtubules; spindle apparatus specifically requires
microtubules.
• High-Yield Clinical Correlation: Many chemotherapeutic
agents target microtubules to inhibit cell division.
• Memory Anchor: “Microtubules move mitotic
chromosomes.”
Q3. A patient with chronic alcohol use develops hepatocyte
swelling after severe hypoxic injury. Cellular sodium and water
accumulation most directly resulted from failure of which
membrane-associated mechanism?
A. Ligand-gated calcium channels
B. Na+/K+-ATPase activity
C. Endocytosis through clathrin-coated pits
The Biologic Basis for Disease in Adults
and Children
9th Edition
Author(s)Julia Rogers
TEST BANK
Q1. A 6-year-old child is diagnosed with a rare inherited
disorder involving defective mitochondrial oxidative
phosphorylation. During periods of fasting, the child develops
profound fatigue, muscle weakness, and lactic acidosis. The
accumulation of lactate most directly reflects failure of which
cellular process?
,A. β-oxidation within peroxisomes
B. Anaerobic glycolysis secondary to impaired ATP production
C. Glycogenolysis within hepatocyte lysosomes
D. Increased pentose phosphate pathway activity
E. Enhanced gluconeogenesis in skeletal muscle
Correct Answer: B
Rationale:
• Clinical Clue: Fasting intolerance with lactic acidosis
suggests impaired aerobic energy generation.
• Mechanism: Dysfunctional oxidative phosphorylation
reduces ATP production, forcing cells to rely on anaerobic
glycolysis with lactate generation.
• Why the Correct Answer Is Right: Anaerobic glycolysis
becomes the major ATP source when mitochondria cannot
effectively use oxygen.
• Why the Other Options Are Wrong:
o A: Peroxisomal β-oxidation does not directly explain
lactate accumulation.
o C: Glycogenolysis occurs in cytoplasm, not lysosomes.
o D: Pentose phosphate activity generates NADPH, not
lactate.
o E: Skeletal muscle is not a major gluconeogenic organ.
, • Exam Trap: Do not confuse mitochondrial failure with
hypoxia alone; both can produce lactic acidosis through
impaired aerobic metabolism.
• High-Yield Clinical Correlation: Mitochondrial diseases
often affect tissues with high energy demand such as
muscle and nervous tissue.
• Memory Anchor: “Broken mitochondria push cells toward
lactate.”
Q2. A researcher selectively disrupts microtubule
polymerization in rapidly dividing tumor cells. Shortly
afterward, the cells arrest during mitosis. Which function is
most directly impaired?
A. Formation of gap junctions
B. Synthesis of ribosomal RNA
C. Segregation of chromosomes during metaphase
D. Oxidative phosphorylation
E. Packaging of proteins within the Golgi apparatus
Correct Answer: C
Rationale:
• Clinical Clue: Arrest during mitosis strongly implicates
spindle dysfunction.
• Mechanism: Microtubules form the mitotic spindle
required for chromosome separation.
, • Why the Correct Answer Is Right: Chromosome alignment
and segregation depend on intact microtubules.
• Why the Other Options Are Wrong:
o A: Gap junctions are formed by connexins.
o B: Ribosomal RNA synthesis occurs in the nucleolus.
o D: Oxidative phosphorylation occurs in mitochondria.
o E: Golgi function relies more on vesicular trafficking
than spindle formation.
• Exam Trap: Microfilaments are commonly confused with
microtubules; spindle apparatus specifically requires
microtubules.
• High-Yield Clinical Correlation: Many chemotherapeutic
agents target microtubules to inhibit cell division.
• Memory Anchor: “Microtubules move mitotic
chromosomes.”
Q3. A patient with chronic alcohol use develops hepatocyte
swelling after severe hypoxic injury. Cellular sodium and water
accumulation most directly resulted from failure of which
membrane-associated mechanism?
A. Ligand-gated calcium channels
B. Na+/K+-ATPase activity
C. Endocytosis through clathrin-coated pits
